#include "tcp_helper.h"

#include "lwip/priv/tcp_priv.h"
#include "lwip/stats.h"
#include "lwip/pbuf.h"
#include "lwip/inet_chksum.h"
#include "lwip/ip_addr.h"

#if !LWIP_STATS || !TCP_STATS || !MEMP_STATS
	#error "This tests needs TCP- and MEMP-statistics enabled"
#endif

/** Remove all pcbs on the given list. */
static void
tcp_remove(struct tcp_pcb* pcb_list)
{
	struct tcp_pcb* pcb = pcb_list;
	struct tcp_pcb* pcb2;

	while(pcb != NULL) {
		pcb2 = pcb;
		pcb = pcb->next;
		tcp_abort(pcb2);
	}
}

/** Remove all pcbs on listen-, active- and time-wait-list (bound- isn't exported). */
void
tcp_remove_all(void)
{
	tcp_remove(tcp_listen_pcbs.pcbs);
	tcp_remove(tcp_active_pcbs);
	tcp_remove(tcp_tw_pcbs);
	fail_unless(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
	fail_unless(MEMP_STATS_GET(used, MEMP_TCP_PCB_LISTEN) == 0);
	fail_unless(MEMP_STATS_GET(used, MEMP_TCP_SEG) == 0);
	fail_unless(MEMP_STATS_GET(used, MEMP_PBUF_POOL) == 0);
}

/** Create a TCP segment usable for passing to tcp_input */
static struct pbuf*
tcp_create_segment_wnd(ip_addr_t* src_ip, ip_addr_t* dst_ip,
                       u16_t src_port, u16_t dst_port, void* data, size_t data_len,
                       u32_t seqno, u32_t ackno, u8_t headerflags, u16_t wnd)
{
	struct pbuf* p, *q;
	struct ip_hdr* iphdr;
	struct tcp_hdr* tcphdr;
	u16_t pbuf_len = (u16_t)(sizeof(struct ip_hdr) + sizeof(struct tcp_hdr) + data_len);
	LWIP_ASSERT("data_len too big", data_len <= 0xFFFF);

	p = pbuf_alloc(PBUF_RAW, pbuf_len, PBUF_POOL);
	EXPECT_RETNULL(p != NULL);
	/* first pbuf must be big enough to hold the headers */
	EXPECT_RETNULL(p->len >= (sizeof(struct ip_hdr) + sizeof(struct tcp_hdr)));

	if(data_len > 0) {
		/* first pbuf must be big enough to hold at least 1 data byte, too */
		EXPECT_RETNULL(p->len > (sizeof(struct ip_hdr) + sizeof(struct tcp_hdr)));
	}

	for(q = p; q != NULL; q = q->next) {
		memset(q->payload, 0, q->len);
	}

	iphdr = (struct ip_hdr*)p->payload;
	/* fill IP header */
	iphdr->dest.addr = ip_2_ip4(dst_ip)->addr;
	iphdr->src.addr = ip_2_ip4(src_ip)->addr;
	IPH_VHL_SET(iphdr, 4, IP_HLEN / 4);
	IPH_TOS_SET(iphdr, 0);
	IPH_LEN_SET(iphdr, htons(p->tot_len));
	IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));

	/* let p point to TCP header */
	pbuf_header(p, -(s16_t)sizeof(struct ip_hdr));

	tcphdr = (struct tcp_hdr*)p->payload;
	tcphdr->src   = htons(src_port);
	tcphdr->dest  = htons(dst_port);
	tcphdr->seqno = htonl(seqno);
	tcphdr->ackno = htonl(ackno);
	TCPH_HDRLEN_SET(tcphdr, sizeof(struct tcp_hdr) / 4);
	TCPH_FLAGS_SET(tcphdr, headerflags);
	tcphdr->wnd   = htons(wnd);

	if(data_len > 0) {
		/* let p point to TCP data */
		pbuf_header(p, -(s16_t)sizeof(struct tcp_hdr));
		/* copy data */
		pbuf_take(p, data, (u16_t)data_len);
		/* let p point to TCP header again */
		pbuf_header(p, sizeof(struct tcp_hdr));
	}

	/* calculate checksum */

	tcphdr->chksum = ip_chksum_pseudo(p,
	                                  IP_PROTO_TCP, p->tot_len, src_ip, dst_ip);

	pbuf_header(p, sizeof(struct ip_hdr));

	return p;
}

/** Create a TCP segment usable for passing to tcp_input */
struct pbuf*
tcp_create_segment(ip_addr_t* src_ip, ip_addr_t* dst_ip,
                   u16_t src_port, u16_t dst_port, void* data, size_t data_len,
                   u32_t seqno, u32_t ackno, u8_t headerflags)
{
	return tcp_create_segment_wnd(src_ip, dst_ip, src_port, dst_port, data,
	                              data_len, seqno, ackno, headerflags, TCP_WND);
}

/** Create a TCP segment usable for passing to tcp_input
 * - IP-addresses, ports, seqno and ackno are taken from pcb
 * - seqno and ackno can be altered with an offset
 */
struct pbuf*
tcp_create_rx_segment(struct tcp_pcb* pcb, void* data, size_t data_len, u32_t seqno_offset,
                      u32_t ackno_offset, u8_t headerflags)
{
	return tcp_create_segment(&pcb->remote_ip, &pcb->local_ip, pcb->remote_port, pcb->local_port,
	                          data, data_len, pcb->rcv_nxt + seqno_offset, pcb->lastack + ackno_offset, headerflags);
}

/** Create a TCP segment usable for passing to tcp_input
 * - IP-addresses, ports, seqno and ackno are taken from pcb
 * - seqno and ackno can be altered with an offset
 * - TCP window can be adjusted
 */
struct pbuf* tcp_create_rx_segment_wnd(struct tcp_pcb* pcb, void* data, size_t data_len,
                                       u32_t seqno_offset, u32_t ackno_offset, u8_t headerflags, u16_t wnd)
{
	return tcp_create_segment_wnd(&pcb->remote_ip, &pcb->local_ip, pcb->remote_port, pcb->local_port,
	                              data, data_len, pcb->rcv_nxt + seqno_offset, pcb->lastack + ackno_offset, headerflags, wnd);
}

/** Safely bring a tcp_pcb into the requested state */
void
tcp_set_state(struct tcp_pcb* pcb, enum tcp_state state, ip_addr_t* local_ip,
              ip_addr_t* remote_ip, u16_t local_port, u16_t remote_port)
{
	u32_t iss;

	/* @todo: are these all states? */
	/* @todo: remove from previous list */
	pcb->state = state;

	iss = tcp_next_iss(pcb);
	pcb->snd_wl2 = iss;
	pcb->snd_nxt = iss;
	pcb->lastack = iss;
	pcb->snd_lbb = iss;

	if(state == ESTABLISHED) {
		TCP_REG(&tcp_active_pcbs, pcb);
		ip_addr_copy(pcb->local_ip, *local_ip);
		pcb->local_port = local_port;
		ip_addr_copy(pcb->remote_ip, *remote_ip);
		pcb->remote_port = remote_port;
	} else if(state == LISTEN) {
		TCP_REG(&tcp_listen_pcbs.pcbs, pcb);
		ip_addr_copy(pcb->local_ip, *local_ip);
		pcb->local_port = local_port;
	} else if(state == TIME_WAIT) {
		TCP_REG(&tcp_tw_pcbs, pcb);
		ip_addr_copy(pcb->local_ip, *local_ip);
		pcb->local_port = local_port;
		ip_addr_copy(pcb->remote_ip, *remote_ip);
		pcb->remote_port = remote_port;
	} else {
		fail();
	}
}

void
test_tcp_counters_err(void* arg, err_t err)
{
	struct test_tcp_counters* counters = (struct test_tcp_counters*)arg;
	EXPECT_RET(arg != NULL);
	counters->err_calls++;
	counters->last_err = err;
}

static void
test_tcp_counters_check_rxdata(struct test_tcp_counters* counters, struct pbuf* p)
{
	struct pbuf* q;
	u32_t i, received;

	if(counters->expected_data == NULL) {
		/* no data to compare */
		return;
	}

	EXPECT_RET(counters->recved_bytes + p->tot_len <= counters->expected_data_len);
	received = counters->recved_bytes;

	for(q = p; q != NULL; q = q->next) {
		char* data = (char*)q->payload;

		for(i = 0; i < q->len; i++) {
			EXPECT_RET(data[i] == counters->expected_data[received]);
			received++;
		}
	}

	EXPECT(received == counters->recved_bytes + p->tot_len);
}

err_t
test_tcp_counters_recv(void* arg, struct tcp_pcb* pcb, struct pbuf* p, err_t err)
{
	struct test_tcp_counters* counters = (struct test_tcp_counters*)arg;
	EXPECT_RETX(arg != NULL, ERR_OK);
	EXPECT_RETX(pcb != NULL, ERR_OK);
	EXPECT_RETX(err == ERR_OK, ERR_OK);

	if(p != NULL) {
		if(counters->close_calls == 0) {
			counters->recv_calls++;
			test_tcp_counters_check_rxdata(counters, p);
			counters->recved_bytes += p->tot_len;
		} else {
			counters->recv_calls_after_close++;
			counters->recved_bytes_after_close += p->tot_len;
		}

		pbuf_free(p);
	} else {
		counters->close_calls++;
	}

	EXPECT(counters->recv_calls_after_close == 0 && counters->recved_bytes_after_close == 0);
	return ERR_OK;
}

/** Allocate a pcb and set up the test_tcp_counters_* callbacks */
struct tcp_pcb*
test_tcp_new_counters_pcb(struct test_tcp_counters* counters)
{
	struct tcp_pcb* pcb = tcp_new();

	if(pcb != NULL) {
		/* set up args and callbacks */
		tcp_arg(pcb, counters);
		tcp_recv(pcb, test_tcp_counters_recv);
		tcp_err(pcb, test_tcp_counters_err);
		pcb->snd_wnd = TCP_WND;
		pcb->snd_wnd_max = TCP_WND;
	}

	return pcb;
}

/** Calls tcp_input() after adjusting current_iphdr_dest */
void test_tcp_input(struct pbuf* p, struct netif* inp)
{
	struct ip_hdr* iphdr = (struct ip_hdr*)p->payload;
	/* these lines are a hack, don't use them as an example :-) */
	ip_addr_copy_from_ip4(*ip_current_dest_addr(), iphdr->dest);
	ip_addr_copy_from_ip4(*ip_current_src_addr(), iphdr->src);
	ip_current_netif() = inp;
	ip_data.current_ip4_header = iphdr;

	/* since adding IPv6, p->payload must point to tcp header, not ip header */
	pbuf_header(p, -(s16_t)sizeof(struct ip_hdr));

	tcp_input(p, inp);

	ip_addr_set_zero(ip_current_dest_addr());
	ip_addr_set_zero(ip_current_src_addr());
	ip_current_netif() = NULL;
	ip_data.current_ip4_header = NULL;
}

static err_t test_tcp_netif_output(struct netif* netif, struct pbuf* p,
                                   const ip4_addr_t* ipaddr)
{
	struct test_tcp_txcounters* txcounters = (struct test_tcp_txcounters*)netif->state;
	LWIP_UNUSED_ARG(ipaddr);

	if(txcounters != NULL) {
		txcounters->num_tx_calls++;
		txcounters->num_tx_bytes += p->tot_len;

		if(txcounters->copy_tx_packets) {
			struct pbuf* p_copy = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
			err_t err;
			EXPECT(p_copy != NULL);
			err = pbuf_copy(p_copy, p);
			EXPECT(err == ERR_OK);

			if(txcounters->tx_packets == NULL) {
				txcounters->tx_packets = p_copy;
			} else {
				pbuf_cat(txcounters->tx_packets, p_copy);
			}
		}
	}

	return ERR_OK;
}

void test_tcp_init_netif(struct netif* netif, struct test_tcp_txcounters* txcounters,
                         ip_addr_t* ip_addr, ip_addr_t* netmask)
{
	struct netif* n;
	memset(netif, 0, sizeof(struct netif));

	if(txcounters != NULL) {
		memset(txcounters, 0, sizeof(struct test_tcp_txcounters));
		netif->state = txcounters;
	}

	netif->output = test_tcp_netif_output;
	netif->flags |= NETIF_FLAG_UP | NETIF_FLAG_LINK_UP;
	ip_addr_copy_from_ip4(netif->netmask, *ip_2_ip4(netmask));
	ip_addr_copy_from_ip4(netif->ip_addr, *ip_2_ip4(ip_addr));

	for(n = netif_list; n != NULL; n = n->next) {
		if(n == netif) {
			return;
		}
	}

	netif->next = NULL;
	netif_list = netif;
}
